Field of the Invention
The invention relates to a bone screw including a longitudinal core member with a helical groove and a helical thread body that is provided in the groove. A width of the groove is greater than a width of a turn of the thread body so that the thread body is accommodated with a tolerance in the groove. This allows the thread body to slide in the groove in a longitudinal direction limited by the sidewalls of the groove. Therefore, the shank of the bone screw may move a limited amount relative to the thread body.
Description of the Related Art
A bone screw having a shank with an elastic or flexible element is known from U.S. 2005/0154390 A1. The known flexible bone screw includes a longitudinal bore and a helical, slot-shaped opening in the wall of the shank. The flexibility is determined by the geometry of the hollow bore and the helical slot-shaped opening. To limit the flexibility or to strengthen the bone screw, a core may be provided in the hollow bore.